Tuesday VO Tech Tip: Reverb is not Noise

Over the past few weeks, I’d been receiving an escalating number of questions about noise reduction tools. My guess is that many voice actors were preparing for the types of less-than-optimum recording spaces encountered when traveling. Each fall, the US Thanksgiving Holiday brings with it a significant amount of travel, which means that auditions and projects get recorded under less than ideal circumstances. The first thing many assume is that they’ll need to reduce noise.

That’s not really wrong. Throw some excited revelry into the mix and it can be difficult to find a recording location far enough removed so that good cheer and familial “discussions” don’t intrude into our audio. Add in the sound of water moving through pipes in the wall and forced air HVAC systems, and it’s easy to build up a noticeable noise floor in any recording. However, focusing solely on noise can cause us to lose track of an equally important issue: reflections in the recording space.

I don’t want to diminish the need to isolate from environmental noise. When first beginning to record, it can be difficult to recognize how much distracting sound exists until you connect a sensitive microphone. As I mention in my recording classes, the human brain is a powerful sonic filter. It will focus on what it deems to be important and other noises get weeded out. Our microphone has no such bias, and picks up everything. That’s why you will sometimes hear the claim that a mic is “too sensitive” when it’s just doing its job.

Background noise has gotten to be a pretty fixable issue. Noise removal tools have improved exponentially over the past few years. Even the most basic “Voice Denoise” tool in Izotope’s RX toolset does a decent job. The recent expansion of algorithmic and neural network-derived approaches have led to even more remarkable and affordable plug-ins like Waves Clarity Vx and Acon Digital’s Extract Dialogue.

However, those tools do not deal with issues caused by reflective surfaces and resonant frequencies. That’s why recordings often still sound bad when we try to record in new spaces. It’s easy to get focused on the noise going on in the next room and not realize how echoey and resonant our nearby environment is. Reverb is not noise.

Those unwanted acoustic reflections are the result of sound waves bouncing around inside our space causing complex audio waveform phase relationships to occur. Relational phase can be a very deep and confusing topic. Suffice to say that echoes influence the audio itself by working within the same frequencies. While “noise” is often distinct from the desired source sound of our voice, reflections tend to interact within the sound itself and therefore become significantly more difficult to extract from our recordings. Reverb can simply be trickier to recognize. If we listen back over speakers in the same space in which we recorded, the reflections tend to be masked by the “liveness” of the space itself. That’s why investing in good studio monitor headphones can be helpful.

Noise reduction tools will not do anything to fix reflection issues. The oft-recommended travel “solution” of a shotgun microphone is also more likely to pick up echoes within the space. It’s important to remember noise and reflection are two largely separate challenges.

To solve echoes and reflections, we need to reach for “DeReverb” tools. However, we’re asking those to take on a much more complex task. It’s easy to go too far with Dereverb or Deroom tools. In doing so, we increase the possibility that the desired signal – our voice – will be negatively impacted. Used too aggressively they can easily create results which sound overprocessed and unusable. They can be tricky tools to use. You may find clients would rather fix those issues themselves.

Of course, the best approach is to fix reflection at the source. After taking time to identify the noise sources in your potential recording space, simply giving a sharp handclap can often give you a sense of how “live” a space is. You’ll hear the slapback echo of your handclap. Minimize that and you may not need to reach for the complex tools after all. Of course, you may need to explain why you are creating forts out of pillows and comforters in the spare room.

Have you tested your studio’s audio quality to make sure it meets professional standards? For a free review of your vocal recordings, please use the upload tool on my Audio Review page.

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